Currently I am running 3x ssd's in raid 0 for my OS. I have 4x 1TB hdd's that I would like to run in raid 10. My motherboard is an asus p6t deluxe. I realize that this motherboard only has 6x sata and 2x sas. Since 3 of the 6 sata ports are being currently used with the ssd's it leaves me with 3 ports being short of 1 for my raid10 config. Would it be possible to use one of the sas ports in cunjunction with the 3 left over sata ports to form a raid 10 array? Or will I need a Raid controller to complete this task?
I'm guessing that your motherboard is similar to my P6T6 WS Revolution in that it has 6 SATA ports on one controller and 2 SATA/SAS ports on another. Unfortunately it's not possible to split a RAID volume across the two controllers using the RAID drivers for the controllers.
If the new drive you're planning to use is for data, you could use software RAID by setting it up inside Windows Disk Manager. For a data volume you don't need the boot capability that the chipset RAID drivers bring to the table. The biggest downside would be that you'd have to deal with two different RAID implementations with different ways of monitoring and handling disk failures.
Software RAID (especially linux/bsd) has no problems using multiple controllers. Windows offers software RAID too, but not in too many advanced configurations. The stripe performance is decent though, i got 500MB/s with multiple controllers on 8 older disks. But don't use software RAID5 on Windows; its only a simple implementation with poor performance and recovery.